Migrate Helpers and Group QA selectors

What does this MR do and why?

Migrates the selector attributes from data-qa-selector to data-testid, for helpers and groups pages, as per gitlab-org/quality/quality-engineering/team-tasks#1822 (closed)

Screenshots or screen recordings

n/a

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

Ensure that affected specs function correctly eg.

CHROME_HEADLESS=false bundle exec bin/qa Test::Instance::All http://gdk.test:3000/ ./qa/specs/features/ee/browser_ui/3_create/repository/assign_code_owners_spec.rb:21

Ensure E2E specs pass, or known issues (see Allure report)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.